Statutory Instruments

A Statutory Instrument (SI) is the principal form in which delegated or secondary legislation is made in Great Britain.
Statutory Instruments are governed by the Statutory Instruments Act 1946.

They replaced Statutory Rules and Orders, made under the Rules Publication Act 1893, in 1948.
Most delegated legislation in Great Britain is made in the form of a Statutory Instrument. (In Northern Ireland, delegated legislation is organised into Statutory Rules, rather than Statutory Instruments.)

The advent of devolution in 1999 resulted in many powers to make Statutory Instruments being transferred to the Scottish Government and Welsh Assembly Government, and oversight to the Scottish Parliament and National Assembly for Wales.

Instruments made by the Scottish Government are now classed separately as Scottish Statutory Instruments.

The Republic of Ireland and Commonwealth countries besides Great Britain also use SIs: see the article Statutory Instruments.